Add database management with SQLAlchemy

Add management of the pvcprov database with SQLAlchemy, to allow
seamless management of the database. Add automatic tasks to the postinst
of the API to execute these migrations.

api-daemon/pvcapid-manage.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+
+# manage.py - PVC Database management tasks
+# Part of the Parallel Virtual Cluster (PVC) system
+#
+#    Copyright (C) 2018-2020 Joshua M. Boniface <joshua@boniface.me>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation, either version 3 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+###############################################################################
+
+import os
+from flask_migrate import Migrate, MigrateCommand
+from flask_script import Manager
+
+from pvcapid.flaskapi import app, db, config
+
+migrate = Migrate(app, db)
+manager = Manager(app)
+
+manager.add_command('db', MigrateCommand)	
+
+if __name__ == '__main__':
+    manager.run()